I just got a pair of Sugoi RS Flex shorts. I have not worn them yet but I am very impressed with the ("super aero" -- that's really what it's called) fabric. Very lightweight, meshy, stretchy, comfortable. Seems like it would be great for hot & humid weather. Lighter than anything else I've seen, really. (AND it's supposed to make you faster!!! ).

They're cut well too. (I always find Sugoi things flattering for some reason).

I lucked out and found a brand new (tags attached) pair in my size on Ebay for $40 and even though I'm going on a spending diet, couldn't resist the deal (they're normally around $120). I had some fears that they wouldn't actually be new, or there would be some gaping hole in a seam or something, but as far as I can tell they're brand new/first quality/real etc .

Shorter inseams are also cooler...

I find Dryline (the fabric that most of the Shebeest shorts -- except their distance short -- are made out of) to be too hot when it's hot out. I have some PI shorts with Ultrasensor, which is OK in the heat (esp in a shorter length), haven't tried the PI microsensor which is supposed to be lighter and more wicking. Castelli lycra tends to be thinner/cooler too in my experience.

Good luck!